Reticulate Evolution in Japanese Sceptridium, including diploid, tetraploid, and hexaploid species (Ophioglossaceae).

This study demonstrated that the Japanese Sceptridium hexaploid is an allopolyploid with a hybrid origin, having a maternal ancestor that is a related species or an ancestor of the tetraploid Japanese S. formosanum, and having a paternal ancestor that is a related species or a common ancestor of the diploid S. nipponicum, S. triangulare, and S. microphyllum. Furthermore, it concluded that the narrow-leaved individuals observed in Japan likely have certain traits fixed due to high self-fertilization, as no genetic differentiation was observed with S. atrovirens. These data were used in phylogenetic and clustering analyses and were obtained through Sanger sequencing and MIG-seq analysis.